Given the lack of specific data points such as selling prices, offers accepted, and listed prices, I will use the new car price and apply depreciation logic. Assuming a new 2021 Porsche 718 Cayman I4 2.0L Turbocharged Standard costs around 300,000 SAR, and considering a depreciation rate of 10% per year, the car would depreciate approximately 30,000 SAR per year. Since the car is 3 years old, the total depreciation would be 90,000 SAR. Therefore, the estimated price would be 300,000 SAR - 90,000 SAR.